


Chained

by DoubleSunday



Category: Undertale (Video Game)
Genre: Ecto-Genitalia (Undertale), Ecto-Vagina (Undertale), Good W. D. Gaster, M/M, Porn with Feelings, W. D. Gaster Is Not Related to Papyrus and Sans
Language: English
Status: Completed
Published: 2021-03-15
Updated: 2021-03-15
Packaged: 2021-03-23 04:33:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,368
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/30049950
Author URL: https://archiveofourown.org/users/DoubleSunday/pseuds/DoubleSunday
Relationships: W. D. Gaster/Sans
Comments: 4
Kudos: 5





	Chained

His wrists hurt. He tried countless times to reposition himself to feel less pain on them, but that was useless seeing as his chains just left marks on the fragile skin. He wished that he could just be let go already, of course he knew why he had them on. He would have left a long time ago if he hadn’t had them on. Still he hoped that this wouldn’t be his eternity, hopefully one day he would be trusted enough to walk around freely. A knock at the door brought him out of his thoughts, it opened to reveal a familiar skeleton.

“Hey there doc.” Sans almost purred out.

“Hello Sans.” He said plainly.

“What’s wrong doc?” Sans got closer, “Aren’t you happy to see me?”

“I would be happier if you let me go.” He looked at the skeleton dead in the eyes.

“You know I can’t do that doc…” Sans got on the bed with him, “We both know you’d run off to the core, can’t go losing you again…”

“Besides.” Sans nuzzled against his chest and purred out, “I missed you today.”

Gaster rolled his eyes and stayed silent.

Sans straddled his hips when he didn’t receive any kind of affection back, “You gotta give me something doc.”

Silence.

“No? Come on doc, don’t make me get it outta you.”

Get it out of him? What could Sans possibly mean by that? He knew that Sans would never hurt him, well physically, well directly.

“You asked for it doc.” Sans said moving lower.

Sans began to run his hands along Gaster’s body, letting out small purrs as he got lower and lower. Soon he got to the taller man’s pants and Gaster knew exactly what he was planning, but wasn’t going to just give him what he wanted that easily. The sudden stillness that went through Gaster’s body didn’t go unnoticed by Sans, he smirked to himself as he continued. He quickly pushed down the taller man’s, taking his underwear with it as they were pushed to his ankles. Gaster shivered as the cold air hit him, after all this time he still wasn’t used to the cold of Snowdin. Sans took the soft white cock into his hand and gave it a small stroke, keeping his eye on Gaster to see his reactions. Gaster kept a straight face as he looked Sans right in the eyes. Sans stuck his tongue out and dragged it along the underside of the length, making sure to curl his tongue around the tip before plunging it into his mouth. It hit the back of his skull almost immediately with how big Gaster was.

“Nothing?” Sans chuckled as he removed Gaster from his mouth.

Sans picked up speed and stroked faster until Gaster was hard enough to stand on his own, “You’re gonna be fun to break.”

Gaster shuddered and Sans grinned wickedly at the reaction, Sans leaned down and put Gaster back in his mouth. Sans swirled his tongue around the tip and sucked a little harder, Gaster gritted his teeth in an attempt to stop himself from making a noise. Sans continued to swirl his tongue around, going farther and farther down as he went on. Gaster managed to stifle his noises so that Sans wouldn’t hear them, it was getting harder and harder. Sans finally pulled the cock out of his mouth, a long string of saliva connecting the two. Sans’ salmon red tongue hung out of his mouth as he caught his breath, once he was breathing at a normal pace again Sans pushed himself upwards.

“Still nothing?” Sans sat back on his knees, “Well, let’s take it up a notch, shall we?”

Sans pulled down his shorts to reveal his magic had formed into a vagina.

“I know this one’s your favorite.” Sans purred as he pulled his shorts off the rest of the way.

Gaster’s breath hitched as he saw the plump vagina, Sans definitely knew what he liked. Sans hovered above Gaster’s length as he lined himself up, when he was certain that he was all good he looked back to Gaster’s face as he slowly sunk down onto it. Sans let out a soft moan as he was fully seated.

“Forgot how full you make me feel.” Sans moaned out, “So big…”

Gaster breathed in deeply and exhaled slowly, he had better self control then Sans thought. Sans began to slowly bounce, moaning as he looked Gaster right in the eyes. When he got no response he bounced faster, small slapping noises began to fill the room along with Sans’s moans. Still no response from Gaster. Sans picked up his pace to the point where it was slightly starting to hurt himself, tears formed at his eyes as he continued to go faster. Tears began to fall from his eyes and down his face, this was really starting to hurt him. Yet Gaster still showed no care.

“P- please Gaster.” Sans cried, “Just give me something.”

Nothing.

“Am I not pretty enough anymore?” He said brokenly as he began to slow down, “D-do you not love me a-anymore?”  
Sans came to a stop and began to cry harder, Gaster stilled as he watched Sans cry.

“What?” Was the only thing that came out of Gaster’s mouth, “What would possibly give you that idea?”

“I’ve seen the way you look at me now, you’re scared of me.” Sans tried to wipe the tears from his eyes but to no avail, “You probably think I’m hideous now.”

“Sans, I think you’re as beautiful as ever.” Gaster said softly, “I love you no matter what you look like.”

“R- really?” Sans looked at Gaster as his tears began to stop.

“Of course, would you please do something for me Sans?” Gaster asked and Sans nodded, “Please take off my chains, I want to touch you again.”

Sans stopped for a moment and thought, he then reached into his jacket and pulled out a small key. He slowly undid Gaster’s chains and pulled back to look at the taller man, Gaster rubbed his wrists thinking about his next move. Suddenly he grabbed Sans and flipped their positions.

“W-what are you doing doc?” Sans asked, a bit scared.

“I’m going to show you just how much I love you.” Gaster brushed his mouth against Sans’ neck, “I’m going to wreck you.”

Sans shuddered and titled his neck so that Gaster could gain access to more of his neck, Gaster compiled by sticking his tongue out and licking all of the bones greedily. Gaster’s hand traveled downwards to rub Sans’ clit, the small skeleton let out a moan and Gaster began to thrust slowly into him.

“G- Gaster please…” Sans gasped out.

“Please what, my love?” Gaster whispered against bone.

“G- go faster.” Sans whimpered, “I need you to go faster.”

Gaster obeyed his command and picked up his pace, rubbing faster and harder with his hand and thrusting into the body below him. Sans gave out more cries for Gaster to go harder and faster, soon all that could be heard in the room was the loud slaps of Gaster’s thrusting and Sans’ pleasure filled cries. Gaster had closed his eyes when he started to get close, he reopened them to see that Sans was crying again and he slowed down out of concern.

“Sans?” Gaster asked breathless, “Are you ok my love?”

“I-I’m fine.” Sans choked out.

“I’m not hurting you am I?” Gaster asked, coming to a full stop.

“No! I just missed you so much.” Sans cried.

Gaster leaned down to bring Sans into a kiss, “I missed you too.”

Gaster picked up his speed again as he kissed Sans. With a muffled scream Sans came, the tightness of his walls sent Gaster over the edge and he followed Sans while still thrusting into him. The two of them were spent, Gaster slowly pulled out of Sans and watched his cum leak out of the now abused entrance. The taller man let out a huff and lied down next to Sans, pulling him close.

“Gaster, I’m sorry…” Sans said, “I just-”

Gaster silenced him with a kiss, “Quiet now Sans, let’s rest.”


End file.
